One of the big beefs with Energy Star for housing is that all it cared about was energy; beat the standard code by 15% and you got it. No matter that the best way to make a house efficient is to make it tight, leading to all kinds of air quality issues. If the moisture inside got too high and you had a poorly draining wall or a lot of thermal bridging you got mold issues. But the new standards toughen up the Energy side (cranking the energy savings up to 20%) and they deal with the air quality issues with " High-efficiency heating and cooling systems engineered to deliver more comfort, moisture control and quiet operation, and equipped with fresh-air ventilation to improve air quality. " Thermal Bridging and Heat Loss

You can pack in all the insulation you like, but if you have thermal bridging you are going to lose heat through the studs. You might even get condensation and mold on the drywall on the inside on really cold days if the interior humidity is too high. So now there are tough standards.

One of the benefits of a house that leaks heat is that it drives the moisture out of the walls. When you build a house tightly and insulate it well, the moisture in the exterior walls acts differently, and can just sit there. So in an energy efficient house you have to take extra care in your moisture management or the house can rot away from the outside.

Because Energy Star homes offer a tightly-sealed and insulated building envelope, a comprehensive package of flashing, moisture barriers, and heavy-duty membrane details is critical to help keep water from roofs, walls, and foundations for improved durability and indoor air quality.

Appliances and Lighting

Other measures include use of Energy Star lighting, appliances and fans.

Third-Party Verification:

Historically a problem, now there will be independent review.

Energy Star qualified homes require verification by independent Home Energy Raters who conduct a comprehensive series of detailed inspections and use specialized diagnostic equipment to test system performance.

Finally, The Realization that Big Houses Need a Tougher Standard:

But the most significant feature is probably the realization that monster houses need a different standard:

Houses of all sizes will continue to be eligible to earn the ENERGY STAR. However, larger homes will be subject to a size-adjustment factor that will reduce the HERS Index Target threshold and require additional energy efficiency measures. The adjustment factor will result in a carbon footprint for a large home that is more in-line with the footprint of an average-size home. This reflects EPA's ultimate goal of minimizing the carbon footprint of new homes rather than exclusively evaluating relative improvement.

This has huge implications. One of the reasons houses got bigger is that they cost less per square foot to build; the builders were mostly adding air as the hard stuff like kitchens, furnaces and lot levies were already paid for. Any energy savings gained by building more efficiently or with more insulation were lost by the bigger size of the house. Now, a 2200 square foot house is the target size, and as it gets larger, the energy consumption standards start climbing.

These are stunning changes. Expect the building industry to go wild and say that they will increase the cost of housing and that the third party inspection system will cost too much time and money and be subject to abuse.

House size issue will be contentious

In particular, the house size issue will be attacked as fundamentally un-American and perhaps even anti-family, making those who want or need a larger house pay for a higher standard than those who do not. Words like socialism and rationing will be thrown around. But it isn't true; for years the builders have been taking advantage of the American obsession with square foot cost and selling progressively bigger houses at progressively cheaper prices; now it will be more linear. There is nothing unfair about that. It is simply eliminating the quantity discount.